1. Field of the Invention
The present invention relates to a distance measuring apparatus, and more particularly, to a distance measuring apparatus that measures a distance to an object on the basis of the time it takes for light, emitted from a light source, to be reflected off the object and be received by the apparatus.
2. Description of the Related Art
In general, a distance measuring apparatus that measures a distance to an object using light, such as laser light, performs the measurement using the time-of-flight (TOF) technique and a position sensitive device (PSD) utilizing the difference in angle of light that is reflected off a local object and a remote object.
The time-of-flight (TOF) method is used to measure a distance by detecting the difference between the time at which a light source emits reference light and a time at which an optical sensor detects the reflected light of the reference light, rebounded from a measured object.
According to the related art, a distance measuring apparatus using light is provided in such a manner that a direction of reference light, emitted from a light source, is orthogonal to a direction of the reflected reference light, rebounded from a measured object and being made incident on an optical sensor.
For example, the distance measuring apparatus according to the related art may include a light source, a first mirror, a second mirror and an optical sensor. The first mirror changes the path of reference light, emitted from the light source, to a perpendicular direction. The second mirror changes the path of the reference light, whose path has been changed by the first mirror, toward the measured object, receives reflected reference light, reflected from the measured object, and changes the path of the reflected light toward the first mirror. The optical sensor receives the reflected light having its path changed by the second mirror. The first mirror may be provided between the optical sensor and the second mirror.
In the configuration of the distance measuring apparatus according to the related art, the reference light, emitted from the light source, and the reflected light, received by the optical sensor, move in difference directions. Therefore, optical paths having predetermined lengths are required to ensure a sufficient distance to focus light on the left, right, top and bottom, which causes an increase in the size of the distance measuring apparatus.